The present invention relates to a building construction for floors, walls or ceilings with a rigid substructure. The construction includes a plurality of parallel joists and at least one covering layer supported by the joists, which joists each include an elongate, form-stable body with a first side that is flat and faces the covering layer and a second side that faces the substructure. The joist body has threaded, through-running holes, spaced from each other and extending between and perpendicularly to the first and second sides, and load-carrying level-adjusting spacer screws that are screwed into the holes with their anterior screw portions protruding from the joist body on its second side to adjust the first side of the joist body to a desired level. The spacer screws have a length such that their posterior screw portions, situated inside the joist body to maintain sufficient thread engagement, have a part-length of at least 10 mm, preferably at least 20 mm, whilst the anterior screw portions have a part-length of at least 1 mm, preferably at least 5 mm, to form an air gap, which extends from the second side of the joist body. Each level-adjusting spacer screw is provided with a central hole, extending from the posterior end of the level-adjusting spacer screw to a location a distance from the anterior end of the level-adjusting spacer screw to form a bottom part with an inner support surface. The level-adjusting spacer screw is arranged to be anchored to the substructure by means of an attachment element, extending through a central hole in the bottom part, an elastic damping body being arranged at the anterior screw portion, which damping body has a central hole and includes an outer part, arranged to form a spring connection between the level-adjusting spacer screw and the substructure, and an inner part, arranged to be received in the central hole in the level-adjusting spacer screw. The invention also relates to joists and level-adjusting spacer screws of the kind described above.
Building constructions of the kind described above are known through SE-501 517 C2 and SE-503 395 C2 and, in practice, have proved to be advantageous for providing good circulation of air and for adjusting the correct level without using chemical fillers. The last-mentioned patent also describes special spring bands or the like for endowing a floor with resilient qualities.
For new constructions and re-constructions, however, sound-proofing requirements have been made more rigorous with respect to sounds from air and forces, such as by stepping, that act upon the building construction and are transmitted below the substructure supporting the building construction.
The object of the present invention is to provide floor constructions and joists for floor constructions that meet the new requirements for air and step sound-proofing.
The floor construction as well as the joists and the level-adjusting spacer screws in accordance with the invention are configured such that the inner part of the damping body forms a resilient engagement element for co-operation with the inner support surface of the bottom part, the attachment element being arranged to extend through the central hole of the damping body, and the inner part has a cross-sectional dimension that is greater than the diameter of the central hole of the bottom part.
In accordance with a preferred embodiment of the invention, the damping body includes an internal stop sleeve, extending through its central hole, for cooperation with the head of the attachment element and the substructure, the attachment element extending through the stop sleeve. It is thereby possible to use an automatic driving-in tool for the attachment elements so that they can be anchored in the substructure without the damping body being compressed to a permanent compressed assembly position.